Bioactive fiber products

ABSTRACT

The invention relates to a bioactive fiber product that, as a bioactively effective constituent, contains only one polyester fiber, which is largely or exclusively made of a polyester having links, which are condensed therewith and which contain phosphorous. The bioactive fiber products are suited for all textile products for which antibacterial, fungicidal, acaricidal and similar effects are sought.

[0001] This invention relates to bioactive fibrous products such asbioactive yarns and textile fabrics such as nonwovens, wovens, knits andthe like and also correspondingly made-up articles such as apparel andunderwear textiles, sport textiles, home textiles and bedding, hygieneand medical textiles, automotive textiles, food packaging, industrialtextiles for building and filtration, diapers, napkins, towels and thelike and also specific bioactive filaments or yarns such as for examplesutures or tampon retrieval cords.

[0002] For an article to be bioactive for the purposes of this inventionit has to perform a biologically active function, i.e., have abactericidal, fungicidal or acaricidal action for example, in short beactive against bacteria, mites, fungi, viruses and similarmicroorganisms.

[0003] It is well known to manufacture bioactive fibrous products. Forinstance, hospital bed curtains which are bioactive in that they have anantimicrobial action are described in America's Textiles Internationalvolume 25 (1996), number 12, page 118. The curtains are made from yarnswhich are based on a fiber blend; the blend contains first aflame-retardant polyester fiber and secondly a cellulose acetate fiberwhich is antimicrobial by virtue of incorporation of the antimicrobialadditive known as Microban B.

[0004] These bioactive curtains are disadvantageous in that first theyhave to be manufactured from a fiber blend and secondly the celluloseacetate fibers have to be separately rendered antimicrobial by additionof an antimicrobial additive.

[0005] Moreover, it is not completely avoidable that the antimicrobialagent will become more or less rapidly washed out during laundering,that the agent can also migrate out of the textile and cause allergiesin sensitive persons.

[0006] Besides, the antibacterial effect diminishes in use.

[0007] The Japanese application JP07305279a published Nov. 21, 1995,describes a polyester fiber which has antibacterial properties and canbe used accordingly. To create the antibacterial action, this Japanesepatent application teaches admixing the polyester with a quaternaryammonium salt of an alkyl phosphate ester.

[0008] The polyester which contains the additive contains polymerizedphosphorus compounds for flame-retardant properties.

[0009] Similarly, products which contain the fibers described there cancause allergies when the admixture migrates out of the fiber, forexample when the textile product is worn or else in the launderingthereof.

[0010] Even though there are already a whole series of textile bioactivefibrous products, there is still a need for improved bioactive fibrousproducts.

[0011] It is an object of the present invention to provide bioactivefibrous products which are permanently bioactive, whose bioactivity isonly minimally reduced by washing and wearing, if at all, which areappreciably less allergenic, if at all, which are simple to produce andhave a broad bioactivity spectrum.

[0012] This object is surprisingly achieved by bioactive fibrousproducts which include as a bioactive component polyester fibers whichconsist exclusively, substantially or partially of a polyestercomprising cocondensed phosphorus-containing chain members. Preferably,the bioactive fibrous products as per the invention contain no furtherbioactive components or additives. Chain member for the purposes of theinvention is to be understood as meaning chain members which aredisposed in the linear chain of the polymer molecule (longest chain),but also in any side chains and branches present.

[0013] The bioactive fibrous products are preferably textile sheetlikestructures such as wovens, knits and nonwovens and also apparel andunderwear textiles, sport textiles, home textiles and bedding, hygieneand medical textiles, automotive textiles, food packaging, industrialtextiles for building and filtration, diapers, napkins, towels and thelike and also specific bioactive filaments or yarns such as for examplesutures or tampon retrieval cords.

[0014] In a particularly advantageous embodiment of the invention,bioactive fibrous products are made-up finished products for hospitaloperation (curtains and bedding in sick rooms, clothing for physiciansand care personnel, OR apparel, towels, jackets for first aiders,dressing material and drapes, covers for patients' wheelchairs, sutures,filters for air conditioners etc.), for veterinary hygiene (includingpest control), for workwear in the pharmaceutical and food industry(overalls, underwear, etc.), for household articles for the kitchen andbathroom (shower curtains, bathmats), for hygiene articles such asinfant diapers, sanitary napkins, adult diapers, underwear for women whohave just given birth and also for sports articles (socks, underwear)and for numerous industrial applications such as for example filters forair conditioners and automobiles. As well as for mass-produced productssuch as waddings, bedfills and shoe liners, finished products formedfrom bioactive fibers are also suitable for very demanding applicationssuch as space travel.

[0015] The bioactive fibers of which the bioactive fibrous products areconstructed can serve as staple fibers, filaments and as monofils forconstructing the bioactive fibrous product. It is possible in thisconnection for the fiber to be constructed entirely from the polyesterhaving the cocondensed phosphorus-containing chain members. But it isalso possible to use so-called multicomponent fibers. Multicomponentfibers combine multiple different raw materials in one fiber. Examplesare bicomponent fibers which are constructed as core-sheath orside-by-side fibers. One part of side-by-side filaments can consist ofthe bioactive polyester component and the other of a nonbioactivematerial such as for example a nonbioactive polyester.

[0016] In the case of core-sheath filaments, it is possible to providethe bioactive component in the core or else in the sheath. Core-sheathfilaments where the sheath component are the bioactive material arepreferred.

[0017] Fibers for the purposes of the invention can be staple fibers,filaments and monofils.

[0018] In a further embodiment of the invention, the bioactive polyesterfibers are used as so-called hybrid fibers or hybrid yarns.

[0019] These hybrid fibers or yarns consist of multiple preferably twopolymer components, of which one has a melting point which is at least10° C. lower than the other. It is possible to use the bioactivepolyester component as low-melting component or else as higher-meltingcomponent.

[0020] With these hybrid yarns it is possible to use higher temperaturesto cause the lower-melting component to melt, which then acts as amatrix for the higher-melting fibrous component or which, by complete orincipient melting, ensures better integrity in the textile fabric; forexample to improve the slip resistance in the case of woven fabrics orthe bonding together of the fibers in the case of nonwovens.

[0021] For both multicomponent yarns and hybrid yarns, the use of thebioactive polyester component as a low-melting component generallyserves to enlarge the surface area by complete or incipient melting, sothat the bioactive performance can be improved.

[0022] It particularly advantageous to use polyesters where thecocondensed phosphorus-containing chain member is derived from thefollowing components:

[0023] The polyester may also incorporate internal esters of the formula2

[0024] where R₁ and R₂ are each as defined in the case of formula 1. Itwill be appreciated that the ring is cleaved in the course ofcocondensation. Preferably, R₁=CH₃.

[0025] The production of corresponding polyester fibers in which thepolyester comprises cocondensed phosphorus-containing chain members isknown per se. Reference is made here to the following German patentapplications or patent specifications, the disclosure content of whichis hereby expressly incorporated herein: DE-OS 2 236 037, DE-OS 2 242002, DE-OS 2 328 00 343, DE-PS 2 346 787, DE-PS 2 454 189.

[0026] The fibers described therein have hitherto been used as such onlyfor their flame retardancy. When bioactive fibrous products were to beproduced, the only option, as indicated at the beginning for example,was to use an additive which was responsible for the bioactive effects.

[0027] It has now been found that, surprisingly, it is possible toproduce fibrous products having bioactive effects simply by using as abioactive component fibers composed of a polyester comprisingcocondensed phosphorus-containing chain members.

[0028] In a further embodiment of the invention, the polyesterscomprising cocondensed phosphorus-containing chain members additionallycontain a bioactive additive to broaden the bioactive spectrumespecially silver compounds, finely divided metallic silver or additivessuch as described for example in EP 116 865, WO 94/15462 and DE 4 106165 or a phosphate glass incorporating silver ions. Such additives areadded during polymer production or to the molten polymer.

[0029] In an advantageous embodiment, the polyester contains silvermetal as an additional additive. In a further particularly preferredembodiment, the elemental silver is present in the form of nanoparticleshaving a diameter of 1 to 500 nanometers. Nanoparticles having adiameter of 1 to 100 and especially 1 to 10 nanometers are particularlyadvantageous. Nanoparticles are commercially available.

[0030] Of particular advantage for the purposes of the invention arefibrous products which contain bioactive core-sheath fibers where thesheath is the bioactive component. It is possible here to use fiberswhere the sheath component is 50% based on the area cross-section of themulticomponent fiber and less especially 15-50%, preferably 15-25%.

[0031] Fibrous products from multicomponent fibers having a thin sheathare very advantageous. First, these fibers are simple to produce in highquality by melt spinning. Polyester fibers, especially core-sheathfibers, in which exclusively bioactive particles are incorporated andwhere the polyester does not have any cocondensed chain members are moredifficult to process by melt spinning. Secondly, the additional effectswhich are to be obtained through the addition of bioactive additives areachievable using an appreciably smaller add. For instance, a product asper the invention where the polyester only contains 0.5% of silverzirconium phosphate as additive gives the same bioactive performance asa product which contains 1% of silver zirconium phosphate and nococondensed phosphate-containing chain members.

[0032] The fibrous products are produced by methods which are familiarto one of ordinary skill in the art, i.e., wovens and formed-loop knitsare produced using customary machines, nonwovens can be produced forexample from staple fibers or from continuous filament fibers here forexample by the spunbond process. Nonwovens, wovens and knits as per theinvention can also be processed to form layered products or compositesand also to form shaped articles.

[0033] It was particularly surprising that it is possible as per theinvention to obtain a product which has bioactive effect merely by usingpolyester fibers which consist of a polyester which comprisescocondensed phosphorus-containing chain members. The view to date wasthat to obtain a bioactive performance it was necessary to add furtheradditives to the polyester or to incorporate other substances.

[0034] The invention makes it possible to produce correspondingbioactive fibrous products simply and quickly. The bioactivity of theproducts is permanent, it is not reduced by laundering, whether withaqueous systems or else by dry cleaning where organic solvents are used.The cocondensed compounds cannot migrate out and lead to an appreciablylower allergy potential, if any, than is the case with prior art fibrousproducts.

[0035] The following example illustrates the invention:

[0036] PET fibers 1.7 dtex 38 mm were ringspun into Nm 50 yarns andprocessed to form a plain drawn-loop knit. Sample 1 is 100% composed ofnormal PET. The fibers in sample 2 were admixed with 1% of silverzirconium phosphate in the polymer melt. Sample 3 is 100% composed offibers of the polyester according to the invention. The three drawn-loopknits were dyed and reduction cleared under the same conditions.

[0037] The bioactivity of the samples was determined in accordance withthe Japanese standard JISL 1902: 1998 Testing method for antibacterialof textiles. The testing germs used were Staphylococcus aureus ATCC6538P and Klebsiella pneumoniae DSM 789.

[0038] This method determines after an incubation time of 18 h thedifference S=Mb−Mc where

[0039] S=biostatic value

[0040] Mb=logarithm of number of active bacteria on unmodified specimenafter an incubation time of 18 h

[0041] Mc=logarithm of number of active bacteria on modified specimenafter an incubation time of 18 h

[0042] The unmodified specimen used was sample 1 composed of 100% normalPET.

[0043] The following log reductions S were measured relative to thesample: Staphylococcus Klebsiella pneumoniae Sample 2 2.2 7.4 Sample 32.6 7.4

[0044] That is, sample 3 according to the invention exhibited in onecase the same and in the second case a superior antimicrobialperformance (log reduction) than a conventional antibacterial modifiedPET fiber.

1. Bioactive fibrous products which include as a bioactive componentpolyester fibers which consist substantially or exclusively ofpolyesters comprising cocondensed phosphorus-containing chain members.2. Bioactive fibrous products according to claim 1, characterized inthat they contain no further bioactive components or additives. 3.Bioactive fibrous products according to claim 1 or 2, characterized inthat they are configured as textile sheetlike structures such as wovens,knits, nonwovens and the like.
 4. Bioactive fibrous products accordingto claim 1 or 2, characterized in that the fibrous products are specificbioactive filaments or yarns such as sutures and the like.
 5. Bioactivefibrous products as per any one of claims 1 to 3, characterized in thatthe bioactive fibrous products made-up products such as apparel andunderwear textiles, sport textiles, home textiles and bedding, hygieneand medical textiles, automotive textiles, food packaging, industrialtextiles for building and filtration, diapers, napkins, towels and thelike and also specific bioactive filaments or yarns such as for examplesutures.
 6. Bioactive fibrous products according to at least one ofclaims 1 to 5, characterized in that the bioactive fiber is present as amulticomponent fiber.
 7. Bioactive fibrous products according to claim6, characterized in that the bioactive fiber is present as a bicomponentfiber.
 8. Bioactive fibrous products according to any one of claims 1 to5, characterized in that the fibers are present as hybrid fibers. 9.Bioactive fibrous products according to at least one of claims 1 to 5,characterized in that the cocondensed phosphorus-containing chainmembers are derived from compounds as per the formula I and/or II wherepreferably R₁=CH₃.


10. Bioactive fibrous products according to claim 1 and any one ofclaims 3 to 6, characterized in that the polyester additionally containsbioactive additives.
 11. Bioactive fibrous products according to claim10, characterized in that the polyester additionally contains bioactivesilver-containing additives.
 12. Bioactive fibrous products according toclaim 10, characterized in that the polyester additionally containssilver zirconium phosphate.
 13. Bioactive fibrous products according toclaim 1 to 12, characterized in that the polyester fibers aremulticomponent core-sheath fibers having a polyester sheath and thesheath fraction is 15-50%, preferably 15-25% based on the areacross-section of the fiber.
 14. Bioactive fibrous products according toclaim 1 and 3 to 13, characterized in that the fibers contain metallicsilver, preferably in the form of nanoparticles.